Some links follow, but if you search the Internet for these words you will find similar ones: neuroplasticity meditation "tibetan monks" "brain scans" structure development.
Following are links to some articles and two paragraphs of each - please follow the links to read the full articles. Also, I first heard about this through Democracy Now, where you may also find a short video interview with a researcher (I will try to post that link below)
Buddha's Brain: Neuroplasticity and Meditation
Of Meditation, Monks, and Music: Dr. Davidson Speaks on Systematic Mind-Body Training
....Other Effects From MeditationDr. Davidson’s group has also studied meditation practitioners with regard to how their practice affects attention—a mental faculty important to processes such as mental focus, perception, memory, and consciousness—and the brain’s circuitry involved.
An NCCAM-funded study by Dr. Davidson and his colleagues looked at the effects of meditation on a task challenging attention and on related brain activity. The type of meditation studied was concentration meditation, which may be described as focusing sustained attention on an object such as the breath or on a small visual stimulus. One group practiced this meditation as part of an intensive retreat, for
3 months and 10 hours per day. They were compared with a control group that had just learned a similar technique and practiced it 20 minutes daily for 1 week. The task on which all participants were tested, before and after their meditation experiences, challenged attention and memory using a rapid series of letters and numbers. All participants improved on this task following meditation, the investigators found. The longer term practitioners, however, improved much more and also showed more efficient use of brain resources important to the task.